Five thousand miles from Japan, UC Berkeley scientists don’t have to read the headlines to know what is happening at a crippled nuclear power plant.

They just need to glimpse at their computer screens.

There, a steady stream of data from Berkeley’s air, rain and creekwater samples shows peaks and troughs of radioactive contamination — posing no threat to Californians’ health, but telling a tragic tale of Japan’s struggle to contain the threat.

“We can find out what’s going on just by looking at the radioisotope signatures,” said research scientist Daniel H. Chivers, sitting at a laptop in the dark basement of the university’s engineering building, where equipment for a routine class was quickly transformed after the accident into a sophisticated radiation detection system.

More than two weeks after an earthquake and tsunami damaged the plant, little official information has come from Japanese authorities about what exactly is being released, and how it is likely to behave.

But the UC Berkeley team, led by nuclear engineering professor Kai Vetter, publishes its daily analysis on the department’s website.

“We can determine whether the release is from the reactors or the spent fuel pools,” says Chivers. “We make an inference based on what we’re seeing. It’s nuclear forensics.”

No concern here

So far they have found the strongest gamma rays from isotopes of iodine-131, but those levels seem to be dropping slightly. They also see tellurium-132, which also seems to have declined a bit. Both of those elements have very short half-lives, although iodine can concentrate in the thyroid gland.

Currently the monitors also show that levels of cesium-134 and cesium-137 have gone up a bit, although they remain very small. Cesium-137 can be dangerous because it is long-lived, with a half-life of 30 years. But it is very diluted in air and water, Vetter said. “The dilution is what will keep us safe,” he said.

Three of the isotopes — iodine, tellurium and cesium-134 — are linked to the crippled reactors. The fourth, cesium-137, could be from both the reactors and the spent fuel rods. The scientists are investigating the ratios of the isotopes to each other to learn more about their origins.

“There is nothing of concern here,” Vetter said. “As long as Japan does not get another 9.0 earthquake “… there is no risk to California.”

“They do not pose long-term risk, so long as the Japan workers are able to shut it down eventually,” he said.

All of the elements show occasional spikes, but even these do not rise to worrisome doses, he said.

The samples, from air and raindrops captured atop the six-story roof of Etcheverry Hall and water trapped from Berkeley’s gurgling Strawberry Creek, provide an analysis that is just as sophisticated as the federal system set up by the Environmental Protection Agency — but far more quickly.

The EPA can quickly measure general levels of radioactivity, but for a more sensitive interpretation, it must send its California data to a national lab in Alabama for analysis, a process that takes one week. The UC Berkeley lab does the same job in 12 to 24 hours.

On Thursday, the California Department of Public Health began posting readings on its website from eight radiation monitors it has operating around the state. The highest levels, in San Luis Obispo, are 1.55 picocuries per cubic meter of air. If someone breathed those levels for a year, they’d be exposed to roughly one-tenth the amount of radiation as if they took an airline flight from San Francisco to New York.

Health department spokesman Michael Sicilia said it takes several days to make the data public because the filters must be removed from the monitors and sent by overnight mail to a lab in Richmond, then processed.

“We could do it quicker if there was more radiation,” said Vetter.

The UC project was launched when the team first heard news of the damaged reactor. Researchers redirected equipment used by the grad school’s Nuclear Instrumentation and Radiation Detection class and started working until midnight, as well as through weekends and spring break.

By measuring the energy of the gamma rays with high precision, they can determine not only the amount of radiation in the sample, but also its energy, which provides a unique fingerprint of a specific radioisotope.

Radiation levels are so low that the samples must be processed in the basement, where sensitive sensors can be shielded.

“What is exciting is to be doing something day to day, something that matters and has an impact on the public,” said Brian Plimley, 25, a San Jose native and Independence High School grad who is a member of the 10-member detection team while earning his doctorate in nuclear engineering. “A lot of our usual work, although it’s on the forefront of the field, is something that 10 years down the line will make a difference.”

The Berkeley team is also excited about this rare chance to learn more about the circuitous route that radiation takes, depending on winds, rain and the half-life properties of the different materials. Low levels of radioactive iodine have even been detected in the atmosphere in South Carolina, North Carolina, Florida, Massachusetts and Pennsylvania, officials told Reuters on Monday.

Vetter said the crisis in Japan, while tragic, was “a major opportunity to study its path here — how radiation dissipates in our environment. And to use that as a service to the community, so we can provide that information to the public. We don’t have a political agenda. Our agenda is doing research and education — that’s why we’re here, an academic university.”

Rare opportunity

The scientists know that when radiation is emitted, its particles latch onto dust and drift with the winds. Some are dropped by rain. Others remain suspended. After the Chernobyl accident in 1986, some nearby villages were spared, while other distant sites were contaminated with the fallout of iodine-131, ingested by grazing cows. Children who drank the milk from those cows showed elevated rates of thyroid cancer.

But the factors that determine its actual route are not well known, said Chivers. Using the new data, “it is one of the few opportunities we have to really add to the knowledge base of how radiation is transported, and how radioactive material falls out. We can determine the pathways of how this would actually get to a human.”

“There are only a few instances where that has been quantified — and this is one,” he said.

Lisa M. Krieger is a science writer at The Mercury News, covering research, scientific policy and environmental news from Stanford University, the University of California, NASA-Ames, U.S. Geological Survey and other Bay Area-based research facilities. Lisa also contributes to the Videography team. She graduated from Duke University with a degree in biology. Outside of work, she enjoys photography, backpacking, swimming and bird-watching.